chore(refactor): make patching child vnode more readable

src/init.ts

@@ -308,8 +308,8 @@ export function init(modules: Array<Partial<Module>>, domApi?: DOMAPI) {
         newStartVnode = newCh[++newStartIdx];
       }
     }
-    if (oldStartIdx <= oldEndIdx || newStartIdx <= newEndIdx) {
-      if (oldStartIdx > oldEndIdx) {
+
+    if (newStartIdx <= newEndIdx) {
       before = newCh[newEndIdx + 1] == null ? null : newCh[newEndIdx + 1].elm;
       addVnodes(
         parentElm,
@@ -319,9 +319,9 @@ export function init(modules: Array<Partial<Module>>, domApi?: DOMAPI) {
         newEndIdx,
         insertedVnodeQueue
       );
-      } else {
-        removeVnodes(parentElm, oldCh, oldStartIdx, oldEndIdx);
     }
+    if (oldStartIdx <= oldEndIdx) {
+      removeVnodes(parentElm, oldCh, oldStartIdx, oldEndIdx);
     }
   }